Thesis (M.D.S.)--University of Hong Kong, 1993.

Thesis (M.D.S.)--University of Hong Kong, 1993. / Also available in print.

No description available.

Master of Science / Department of Horticulture, Forestry, and Recreation Resources / Rhonda R. Janke / Petiole sap nitrate-nitrogen (NO3-N) analysis with handheld meters is a valuable tool in applying in-season nitrogen (N) for many crops. Sufficiency levels have been determined for several leafy green crops, including lettuce (Lactuca sativa L.) and cabbage (Brassica oleracea L.), but not for pac choi (Brassica rapa L.). The response of pac choi to different fertilizer rates and sources [conventional and organic] has established optimal soluble N application rates and Cardy meter sufficiency ranges. Greenhouse experiments were conducted during summer and fall of 2008 in Manhattan, KS. Conventional soluble fertilizer was formulated from inorganic salts with a 4 NO3-N: 1 ammonium ratio. Phosphorus was held at 1.72mM and K at 0.83mM for all treatment levels. The organic soluble fertilizer, fish hydrolyzate (2N:1.72P:0.83K), was diluted to provide the same N levels as with conventional treatments. Both fertilizers were applied at rates of 0, 32, 75, 150, 225, 300, and 450 mg. L-1. Seedlings were transplanted and fertilizer application began at 18 days. Plants were harvested at seven weeks (five weeks post transplanting) after receiving 15 fertilizer applications during production. Samples of the most recently matured leaves were harvested weekly and analyzed for petiole sap NO3-N and leaf blade total N concentration. Leaf count, leaf length, and chlorophyll content were also measured weekly. Fresh and dry weights were determined on whole shoots and roots. Optimum yield was achieved at the 150 mg. L-1 fertility rate with both conventional and organic fertilizers. Field and high tunnel experiments were conducted during fall 2008 to validate the sufficiency ranges obtained from the greenhouse studies. Based on field and high tunnel results, sufficiency levels of NO3-N for pac choi petiole sap during weeks 2 to 3 of production were 800-1500 mg. L-1, and then dropped to 600-1000 mg. L-1 during weeks 4 through harvest for both conventional and organic fertilizers sources. These ranges could vary based on the variety of the crop, the fertility of soil, and certain environmental factors such as photoperiod, light intensity. However, we found that petiole sap nitrate always increased to the point associated with the maximum biomass, followed by a plateau where sap nitrate remained constant. This characteristic of the Cardy meter can provide the growers with a practical methodology to generate their standard curves under specific conditions to guide in-season N applications. Total N in leaf tissue showed fewer fertilizer rate effects than petiole sap NO3-N. Chlorophyll content was not useful in evaluating pac choi N status.

Background: Drugs targeting angiogenic pathway remain the mainstay of treatment for metastatic renal cell carcinoma (mRCC). Tyrosine Kinase Inhibitors (TKI) as Sunitinib, Pazopanib as single agents and humanised monoclonal antibody bevacizumab (Bev) in combination with Interferon- α2a (IFN) have established as the first-line therapy for mRCC. Despite improvements in treatment, there are multiple questions which remain unanswered. In the combination of Bev and IFN, the respective role of each drug and whether any additional anti-angiogenic activity is gained by adding IFN to Bev remains unknown. As the clinical benefit obtained with these cytostatic agents does not always correlate with the conventional response assessment techniques as RECIST, it is necessary to reconsider the methods by which we assess benefit from these therapies. In this thesis, I report three studies aiming to answer these questions. Methods: With the clinical trial reported here, I explore whether Bev induced changes in vascular parameters measured by Dynamic Contrast Enhanced MRI (DCE-MRI) is significantly enhanced by the addition of IFN. In a phase II, randomised, open labelled, multicentre trial, treatment naïve mRCC patients were randomised to receive Bev on its own or in combination with a low dose (3MU) or standard dose (9MU) IFN. DCE-MRI was used to assess the changes in vascularity with the primary endpoint being, changes in transfer coefficient (Ktrans) after six weeks of treatment. I also report two retrospective imaging-based studies, using contrast-enhanced CT scans, performed to improve the methodology of response assessment for these antiangiogenic therapeutics. Here I explore the use of a) combining changes in size and arterial phase contrast enhancement measured using CT scan and b) changes in CT texture as methods of therapeutic response assessment in mRCC patients treated with TKI. Results: With the phase 2 clinical trial, we faced significant difficulty in recruitment as a result of restrictions in access to treatment in NHS, other competing studies and restrictions proposed by the DCE-MRI inclusion criteria. With slow recruitment, an unplanned analysis was performed after 21 patients were recruited. Analysis of primary endpoint showed no trend in the difference between arms with no correlation found between change in Ktrans and addition of IFN to bevacizumab. Effect size analysis performed due to the small numbers recruited failed to show any significance in the observed difference in Ktrans. Change in Ktrans and Kep may identify a group of patients likely to have PFS > 6 months, but this observation needs to evaluation in a larger sample size. Measuring size and change in arterial phase enhancement retrospectively using CT, a new criterion "modified" Choi, which prerequisite a combination of a decrease in arterial phase density by 15% and a decrease in size by 10% for response was proposed. Response assessment was measured with RECIST, Choi and modified Choi individually in 20 evaluable patients retrospectively and clinical benefit compared with Kaplan-Meier statistics and Log-Rank test. Response assessment as defined by the modified Choi criteria successfully identified patients who received clinical benefit from the treatment. Time to progression (TTP) was 448 days for the partial response and 89 days for stable disease as per the new criteria which were statistically significant with a p-value of 0.002. The second retrospective analysis explored the textural changes in enhanced CT scan. Performed in collaboration with researchers from Brighton University who developed the software algorithm used to assess changes in entropy and uniformity, 87 metastases from 39 patients with mRCC were analysed at baseline and after two cycles of TKI treatment. Textural parameters and response assessment criteria were correlated with TTP. After two cycles of TKI, the decrease in tumour entropy was 3%-45%, and increase in uniformity was 5%-21%. At a threshold change of -2% with uniformity, on a coarse scale of 2.5, the textural change was able to separate responders from non-responders. With Kaplan-Meier analysis comparing all four criteria, the percentage change in uniformity was statistically more significant than for RECIST, Choi, and Modified Choi criteria. Cox regression analysis showed that texture uniformity was an independent predictor of time to progression. Discussion: With the studies reported here, I was able to demonstrate the importance of improving the methodology in assessment of therapeutic response to targeted anti-angiogenic therapy in metastatic renal cell carcinoma. Even though the clinical trial, terminated early due to slow recruitment, did not reach its primary endpoint, changes in other vascular parameters as Kep combined with changes Ktrans showed tendency towards identifying a group of patients who derived clinical benefit of >6months with these therapies. This is particularly exciting as given the vascular stabilisation effect proposed for bevacizumab, the effusion parameter Kep may be a better tool in assessing response rather than Ktrans and warrants further assessment in a larger cohort. Modified choi criterion and textural analysis are two important methodological improvements in response assessment of cytostatic anti-angiogenic therapy. In the analyses reported here, both techniques have shown superiority over RECIST in response assessment and differentiating mRCC patients who is likely to gain clinical benefit by TKI therapy. Validation of these criteria on a larger patient cohort is important. As these criterions are assessed on standard enhanced CT scans, incorporating these criteria, especially modified choi criterion, as part of standard CT assessment could be performed and will provide a real world validation. Retrospective assessment using larger cohort of patients from previous phase 3 trials or inclusion of these parameters prospectively in phase 3 trials would also help us in evaluating these modalities further.

Thesis (M. Ed.)--University of Hong Kong, 1996. / Includes bibliographical references (leaf 134-141).

Thesis (M.Ed.)--University of Hong Kong, 1996. / Includes bibliographical references (leaves 134-141). Also available in print.

Die Arbeit befaßt sich mit Methoden der Identifikation von Schwingungsursachen anhand gemessener Schwingungssignale an Maschinen mit ungleichförmig übersetzenden Getrieben. Den technischen Hintergrund bilden die Verarbeitungsmaschinen, die als ein Haupteinsatzgebiet der auch als Mechanismen bezeichneten Getriebe gelten. Es werden eine ganze Reihe mechanismentypischer Schwingungsursachen untersucht, die im wesentlichen auf Elastizitäten, veränderliche Parameter, Spiel, Reibung und Unstetigkeiten in den Lagefunktionen zurückzuführen sind. Neben den traditionellen Methoden der Signalanalyse gilt das Hauptaugenmerk den neuen Methoden der Zeit-Frequenz-Analyse, die dem zumeist instationären Charakter der durch die Mechanismen verursachten Schwingungen gerecht werden. Dazu zählen vor allem lineare Transformationen wie die Kurzzeit-Fourier- oder die Wavelet-Transformation, quadratische Verteilungen aus Cohen's Klasse wie die Wigner-Ville und die Choi-Williams Verteilung oder auch höhere Transformationen wie die Adaptive Optimal Kernel oder die Reassignment Methode. Die Untersuchungen münden in einer tabellarischen Zusammenstellung der gefundenen Merkmale. Diese soll der Unterstützung der praktischen Signalanalyse bei Mechanismenschwingungen dienen. Die Anwendung der zur Verfügung stehenden Mittel und Methoden wird an zahlreichen Beispielen aus dem Bereich der Schwingungsdiagnose an Verarbeitungsmaschinen demonstriert. / This thesis deals with methods to identify causes of vibrations by investigation of messured signals at machines with mechanisms (with varying velocity ratio). The technical background is the field of manufacturing machines, the main application of such mechanisms. Inspected are the most typical causes of vibrations at mechanisms that comes with elasticity, variable parameters, clearance, friction or nonsmooth transferfunctions. There are used both, traditional methods of signal analysis and time-frequency-analysis methods that are especially advantageous for the often instationary vibrations at this kind of machines. Linear transformations like the Short-Time-Fourier- or the Wavelet-Transformation, quadratic distributions from Cohe's Class like the Wigner-Ville- or the Choi-Williams-Distribution and higher order transformations like the Adaptive Optimal Kernel or the Reassignment Method are used in this Paper. The investigation leads into a tabular form of characteristics wich should be used for identification of vibrational causes during vibrational analysis. The use of available methods is demonstrated by solving various examples on real manufactoring machines.

Die Arbeit befaßt sich mit Methoden der Identifikation von Schwingungsursachen anhand gemessener Schwingungssignale an Maschinen mit ungleichförmig übersetzenden Getrieben. Den technischen Hintergrund bilden die Verarbeitungsmaschinen, die als ein Haupteinsatzgebiet der auch als Mechanismen bezeichneten Getriebe gelten. Es werden eine ganze Reihe mechanismentypischer Schwingungsursachen untersucht, die im wesentlichen auf Elastizitäten, veränderliche Parameter, Spiel, Reibung und Unstetigkeiten in den Lagefunktionen zurückzuführen sind. Neben den traditionellen Methoden der Signalanalyse gilt das Hauptaugenmerk den neuen Methoden der Zeit-Frequenz-Analyse, die dem zumeist instationären Charakter der durch die Mechanismen verursachten Schwingungen gerecht werden. Dazu zählen vor allem lineare Transformationen wie die Kurzzeit-Fourier- oder die Wavelet-Transformation, quadratische Verteilungen aus Cohen's Klasse wie die Wigner-Ville und die Choi-Williams Verteilung oder auch höhere Transformationen wie die Adaptive Optimal Kernel oder die Reassignment Methode. Die Untersuchungen münden in einer tabellarischen Zusammenstellung der gefundenen Merkmale. Diese soll der Unterstützung der praktischen Signalanalyse bei Mechanismenschwingungen dienen. Die Anwendung der zur Verfügung stehenden Mittel und Methoden wird an zahlreichen Beispielen aus dem Bereich der Schwingungsdiagnose an Verarbeitungsmaschinen demonstriert. - - - Diese Version ersetzt eine ältere Version, Grund: Formatkonvertierung postscript zu pdf. Der Inhalt unterscheidet sich in der Qualität der Abb. 4.23a und 4.23b auf Seite 97 sowie aller Abbildungen auf Seite 111. Der Zugriff auf die Original-Abb. ist über die ältere Version oder die gedruckte Ausgabe möglich. Die gedruckte Ausgabe der Dissertation ist in der Universitätsbibliothek Chemnitz entleihbar. / This thesis deals with methods to identify causes of vibrations by investigation of messured signals at machines with mechanisms (with varying velocity ratio). The technical background is the field of manufacturing machines, the main application of such mechanisms. Inspected are the most typical causes of vibrations at mechanisms that comes with elasticity, variable parameters, clearance, friction or nonsmooth transferfunctions. There are used both, traditional methods of signal analysis and time-frequency-analysis methods that are especially advantageous for the often instationary vibrations at this kind of machines. Linear transformations like the Short-Time-Fourier- or the Wavelet-Transformation, quadratic distributions from Cohe's Class like the Wigner-Ville- or the Choi-Williams-Distribution and higher order transformations like the Adaptive Optimal Kernel or the Reassignment Method are used in this Paper. The investigation leads into a tabular form of characteristics wich should be used for identification of vibrational causes during vibrational analysis. The use of available methods is demonstrated by solving various examples on real manufactoring machines. - - - This version replaces an older version, reason is conversion of format from postscript to pdf. Content is different in quality of pictures 4.23a and 4.23b on page 97 and all pictures on page 111. Please see the original pictures in the older version or the printed version. The printed version is borrowable at the Library of Chemnitz University of Technology.

Die Arbeit befaßt sich mit Methoden der Identifikation von Schwingungsursachen anhand gemessener Schwingungssignale an Maschinen mit ungleichförmig übersetzenden Getrieben. Den technischen Hintergrund bilden die Verarbeitungsmaschinen, die als ein Haupteinsatzgebiet der auch als Mechanismen bezeichneten Getriebe gelten. Es werden eine ganze Reihe mechanismentypischer Schwingungsursachen untersucht, die im wesentlichen auf Elastizitäten, veränderliche Parameter, Spiel, Reibung und Unstetigkeiten in den Lagefunktionen zurückzuführen sind. Neben den traditionellen Methoden der Signalanalyse gilt das Hauptaugenmerk den neuen Methoden der Zeit-Frequenz-Analyse, die dem zumeist instationären Charakter der durch die Mechanismen verursachten Schwingungen gerecht werden. Dazu zählen vor allem lineare Transformationen wie die Kurzzeit-Fourier- oder die Wavelet-Transformation, quadratische Verteilungen aus Cohen's Klasse wie die Wigner-Ville und die Choi-Williams Verteilung oder auch höhere Transformationen wie die Adaptive Optimal Kernel oder die Reassignment Methode. Die Untersuchungen münden in einer tabellarischen Zusammenstellung der gefundenen Merkmale. Diese soll der Unterstützung der praktischen Signalanalyse bei Mechanismenschwingungen dienen. Die Anwendung der zur Verfügung stehenden Mittel und Methoden wird an zahlreichen Beispielen aus dem Bereich der Schwingungsdiagnose an Verarbeitungsmaschinen demonstriert. / This thesis deals with methods to identify causes of vibrations by investigation of messured signals at machines with mechanisms (with varying velocity ratio). The technical background is the field of manufacturing machines, the main application of such mechanisms. Inspected are the most typical causes of vibrations at mechanisms that comes with elasticity, variable parameters, clearance, friction or nonsmooth transferfunctions. There are used both, traditional methods of signal analysis and time-frequency-analysis methods that are especially advantageous for the often instationary vibrations at this kind of machines. Linear transformations like the Short-Time-Fourier- or the Wavelet-Transformation, quadratic distributions from Cohe's Class like the Wigner-Ville- or the Choi-Williams-Distribution and higher order transformations like the Adaptive Optimal Kernel or the Reassignment Method are used in this Paper. The investigation leads into a tabular form of characteristics wich should be used for identification of vibrational causes during vibrational analysis. The use of available methods is demonstrated by solving various examples on real manufactoring machines.